<template>
  <div :ref="'wrap' + props.classOption['key']">
    <div v-if="navigation" :style="leftSwitch" :class="leftSwitchClass" @click="leftSwitchClick">
      <slot name="left-switch"></slot>
    </div>
    <div v-if="navigation" :style="rightSwitch" :class="rightSwitchClass" @click="rightSwitchClick">
      <slot name="right-switch"></slot>
    </div>
    <div
      :ref="'realBox' + props.classOption['key']"
      :style="pos"
      @mouseenter="enter"
      @mouseleave="leave"
      @mousewheel.passive="wheel"
    >
      <div :ref="'slotList' + props.classOption['key']" :style="float">
        <slot></slot>
      </div>
      <div :style="float" v-html="copyHtml"></div>
    </div>
  </div>
</template>

<script setup lang="ts">
import { computed, ref, unref, nextTick } from 'vue'
import type { CSSProperties, PropType } from 'vue'
import { tryOnMounted, tryOnUnmounted, templateRef, useDebounceFn } from '@vueuse/core'
import * as utilsMethods from './utils'
const { animationFrame, copyObj } = utilsMethods
animationFrame()

defineOptions({
  name: 'ReSeamlessScroll'
})

const props = defineProps({
  data: {
    type: Array as PropType<any>
  },
  classOption: {
    type: Object as PropType<any>
  }
})

const emit = defineEmits<{
  (e: 'scrollEnd'): void
}>()

const xPos = ref<number>(0)
const yPos = ref<number>(0)
const delay = ref<number>(0)
const height = ref<number>(0)
// 外容器宽度
const width = ref<number>(0)
// 内容实际宽度
const realBoxWidth = ref<number>(0)
const realBoxHeight = ref<number>(0)
const copyHtml = ref('')
// single 单步滚动的定时器
let singleWaitTime: number | null = null
// move动画的animationFrame定时器
let reqFrame: number | null = null
// mouseenter mouseleave 控制scrollMove()的开关
let isHover = false
let ease = 'ease-in'

if (props.classOption['key'] === undefined) {
  // eslint-disable-next-line vue/no-mutating-props
  props.classOption['key'] = 0
}

const wrap = templateRef<HTMLElement | null>(`wrap${props.classOption['key']}`, null)
const slotList = templateRef<HTMLElement | null>(`slotList${props.classOption['key']}`, null)
const realBox = templateRef<HTMLElement | null>(`realBox${props.classOption['key']}`, null)

const leftSwitchState = computed(() => unref(xPos) < 0)

const rightSwitchState = computed(() => {
  return Math.abs(unref(xPos)) < unref(realBoxWidth) - unref(width)
})

const defaultOption = computed(() => {
  return {
    //步长，滚动速度，越大越快
    step: 0.5,
    //启动无缝滚动最小数据数
    limitMoveNum: 5,
    //是否启用鼠标hover控制
    hoverStop: true,
    // bottom 往下 top 往上(默认) left 向左 right 向右
    direction: 'top',
    //单条数据高度有值hoverStop关闭
    singleHeight: 0,
    //单条数据宽度有值hoverStop关闭
    singleWidth: 0,
    //单步停止等待时间
    waitTime: 1000,
    switchOffset: 30,
    autoPlay: true,
    navigation: false,
    switchSingleStep: 134,
    switchDelay: 400,
    switchDisabledClass: 'disabled',
    // singleWidth/singleHeight 是否开启rem度量
    isSingleRemUnit: false
  }
})

const options = computed(() => {
  // @ts-expect-error
  return copyObj({}, unref(defaultOption), props.classOption)
})

const leftSwitchClass = computed(() => {
  return unref(leftSwitchState) ? '' : unref(options).switchDisabledClass
})

const rightSwitchClass = computed(() => {
  return unref(rightSwitchState) ? '' : unref(options).switchDisabledClass
})

const leftSwitch = computed((): CSSProperties => {
  return {
    position: 'absolute',
    margin: `${unref(height) / 2}px 0 0 -${unref(options).switchOffset}px`,
    transform: 'translate(-100%,-50%)'
  }
})

const rightSwitch = computed((): CSSProperties => {
  return {
    position: 'absolute',
    margin: `${unref(height) / 2}px 0 0 ${unref(width) + unref(options).switchOffset}px`,
    transform: 'translateY(-50%)'
  }
})

const isHorizontal = computed(() => {
  return unref(options).direction !== 'bottom' && unref(options).direction !== 'top'
})

const float = computed((): CSSProperties => {
  return unref(isHorizontal) ? { float: 'left', overflow: 'hidden' } : { overflow: 'hidden' }
})

const pos = computed(() => {
  return {
    transform: `translate(${unref(xPos)}px,${unref(yPos)}px)`,
    transition: `all ${ease} ${unref(delay)}ms`,
    overflow: 'hidden'
  }
})

const navigation = computed(() => {
  return unref(options).navigation
})

const autoPlay = computed(() => {
  if (unref(navigation)) return false
  return unref(options).autoPlay
})

const scrollSwitch = computed(() => {
  // 从 props 解构出来的 属性 不再具有响应性.
  return (props.data as any).length >= unref(options).limitMoveNum
})

const hoverStopSwitch = computed(() => {
  return unref(options).hoverStop && unref(autoPlay) && unref(scrollSwitch)
})

const baseFontSize = computed(() => {
  return unref(options).isSingleRemUnit ? parseInt(window.getComputedStyle(document.documentElement, null).fontSize) : 1
})

const realSingleStopWidth = computed(() => {
  return unref(options).singleWidth * unref(baseFontSize)
})

const realSingleStopHeight = computed(() => {
  return unref(options).singleHeight * unref(baseFontSize)
})

const step = computed(() => {
  let singleStep
  const step = unref(options).step
  if (unref(isHorizontal)) {
    singleStep = unref(realSingleStopWidth)
  } else {
    singleStep = unref(realSingleStopHeight)
  }
  if (singleStep > 0 && singleStep % step > 0) {
    throw '如果设置了单步滚动，step需是单步大小的约数，否则无法保证单步滚动结束的位置是否准确'
  }
  return step
})

function reset() {
  xPos.value = 0
  yPos.value = 0
  scrollCancle()
  scrollInitMove()
}

function leftSwitchClick() {
  if (!unref(leftSwitchState)) return
  // 小于单步距离
  if (Math.abs(unref(xPos)) < unref(options).switchSingleStep) {
    xPos.value = 0
    return
  }
  xPos.value += unref(options).switchSingleStep
}

function rightSwitchClick() {
  if (!unref(rightSwitchState)) return
  // 小于单步距离
  if (unref(realBoxWidth) - unref(width) + unref(xPos) < unref(options).switchSingleStep) {
    xPos.value = unref(width) - unref(realBoxWidth)
    return
  }
  xPos.value -= unref(options).switchSingleStep
}

function scrollCancle() {
  cancelAnimationFrame(reqFrame || 0)
}

function enter() {
  if (unref(hoverStopSwitch)) scrollStopMove()
}

function leave() {
  if (unref(hoverStopSwitch)) scrollStartMove()
}

function scrollMove() {
  // 鼠标移入时拦截scrollMove()
  if (isHover) return
  // 进入move立即先清除动画 防止频繁touchMove导致多动画同时进行
  // scrollCancle();
  reqFrame = requestAnimationFrame(function () {
    //实际高度
    const h = unref(realBoxHeight) / 2
    //宽度
    const w = unref(realBoxWidth) / 2
    const { direction, waitTime } = unref(options)
    if (direction === 'top') {
      // 上
      if (Math.abs(unref(yPos)) >= h) {
        emit('scrollEnd')
        yPos.value = 0
      }
      yPos.value -= step.value
    } else if (direction === 'bottom') {
      // 下
      if (unref(yPos) >= 0) {
        emit('scrollEnd')
        yPos.value = h * -1
      }
      yPos.value += step.value
    } else if (direction === 'left') {
      // 左
      if (Math.abs(unref(xPos)) >= w) {
        emit('scrollEnd')
        xPos.value = 0
      }
      xPos.value -= step.value
    } else if (direction === 'right') {
      // 右
      if (unref(xPos) >= 0) {
        emit('scrollEnd')
        xPos.value = w * -1
      }
      xPos.value += step.value
    }
    if (singleWaitTime) {
      clearTimeout(singleWaitTime)
    }
    if (unref(realSingleStopHeight)) {
      //是否启动了单行暂停配置
      if (Math.abs(unref(yPos)) % unref(realSingleStopHeight) < unref(step)) {
        // 符合条件暂停waitTime
        singleWaitTime = setTimeout(() => {
          scrollMove()
        }, waitTime) as unknown as number
      } else {
        scrollMove()
      }
    } else if (unref(realSingleStopWidth)) {
      if (Math.abs(unref(xPos)) % unref(realSingleStopWidth) < unref(step)) {
        // 符合条件暂停waitTime
        singleWaitTime = setTimeout(() => {
          scrollMove()
        }, waitTime) as unknown as number
      } else {
        scrollMove()
      }
    } else {
      scrollMove()
    }
  })
}

function scrollInitMove() {
  nextTick(() => {
    const { switchDelay } = unref(options)
    //清空copy
    copyHtml.value = ''
    if (unref(isHorizontal)) {
      height.value = unref(wrap)?.offsetHeight ?? 0
      width.value = unref(wrap)?.offsetWidth ?? 0
      let slotListWidth = unref(slotList)?.offsetWidth ?? 0
      // 水平滚动设置warp width
      if (unref(autoPlay)) {
        // 修正offsetWidth四舍五入
        slotListWidth = slotListWidth * 2 + 1
      }
      if (unref(realBox)) {
        unref(realBox)!.style.width = slotListWidth + 'px'
      }
      realBoxWidth.value = slotListWidth
    }

    if (unref(autoPlay)) {
      ease = 'ease-in'
      delay.value = 0
    } else {
      ease = 'linear'
      delay.value = switchDelay
      return
    }

    // 是否可以滚动判断
    if (unref(scrollSwitch)) {
      let timer
      if (timer) clearTimeout(timer)
      copyHtml.value = unref(slotList)?.innerHTML ?? ''
      setTimeout(() => {
        realBoxHeight.value = unref(realBox)?.offsetHeight ?? 0
        scrollMove()
      }, 0)
    } else {
      scrollCancle()
      yPos.value = xPos.value = 0
    }
  })
}

function scrollStartMove() {
  //开启scrollMove
  isHover = false
  scrollMove()
}

function scrollStopMove() {
  //关闭scrollMove
  isHover = true
  // 防止频频hover进出单步滚动,导致定时器乱掉
  if (singleWaitTime) clearTimeout(singleWaitTime)
  scrollCancle()
}

// 鼠标滚轮事件
function wheel(e: { deltaY: number }) {
  if (unref(options).direction === 'left' || unref(options).direction === 'right') return
  useDebounceFn(() => {
    e.deltaY > 0 ? (yPos.value -= step.value) : (yPos.value += step.value)
  }, 50)()
}

tryOnMounted(() => {
  scrollInitMove()
})

tryOnUnmounted(() => {
  scrollCancle()
  if (singleWaitTime) {
    clearTimeout(singleWaitTime)
  }
})

defineExpose({
  reset
})
</script>
